This invention relates generally to wireless systems including wireless local area network devices.
Packet-based wireless local area network (LAN) devices enable a plurality of clients to be coupled together with a server without the need for extensive wiring. The IEEE 802.11 family of standards (IEEE Standard 802.11 available from the Institute of Electrical and Electronics Engineers, New York, N.Y.) describes a standard for wireless LAN systems. It involves the use of either 2.4 GHz Industrial, Scientific and Medical (ISM) or 5 GHz communication frequency bands. These bands are minimally regulated and, as a result, other interfering wireless devices (that do not comply with the IEEE 802.11 standard) may be transmitting in the same area in the same band.
As an example, within a given office that is utilizing a system compliant with the IEEE 802.11 standard, other individuals may utilize devices compliance with the Bluetooth specification (V.1.0, Dec. 1, 1999) for wireless devices. Like the IEEE 802.11 standard, the Bluetooth devices also operate in the 2.4 GHz ISM band.
Interference may result between the Bluetooth and packet-based wireless LAN devices. Generally, in the case of Bluetooth devices, their power output is relatively small relative to the wireless LAN devices. However, a proximate Bluetooth device may adversely affect and interfere with the reception of a local wireless LAN device. Another device in the LAN may transmit to a local LAN device proximate a Bluetooth transmitter. The remote LAN transmitter may have no idea that a lower power Bluetooth transmitter may also be transmitting. As a result, interference may occur which varies depending on the receiver that is receiving the signal.
Proposals for mitigating the effects of interference between Bluetooth and packet-based wireless LANs operating in the same frequency band generally have relied upon frequency orthogonality. However, such techniques may be ineffective when the Bluetooth and wireless LAN devices are in close proximity which, of course, is when the interference is most substantial.
Thus, there is a need for a way to mitigate interference between wireless devices operating on different standards within the same frequency band. In addition, there is a need for a system that accommodates for the problems that arise when various devices in a wireless network are not aware that receivers in that network may be proximate to non-compliant transmitters operating within the same frequency band.